Fresh install of Windows 7 after hard drive failure: recovery key used on original drive no longer works?

I just had my hard drive replaced recently after it starting giving boot warnings about impending failure. The IT department at my uni replaced the drive, loaded their standard Win7 install, and restored all of my documents and files. Booting Mozilla for the first time on that install, I had all of my bookmarks, setting, passwords, etc. already there (FF even gave me the dialog to restore the last session before the drive replacement.)

But, since their install is awful (tons of bloatware, obnoxious account management and admin privileges, etc.), I decided to go about putting my own copy of 7 on just as I want it. Having learned my lesson with my Sync account last time I did this, I checked to make sure that I still had the recovery key from the original drive/installation (not the IT install.) Now, when I try to use my recovery key, Sync says it's the wrong one, and that "your Recovery Key has been changed with another device." I haven't touched the Key since I first generated it, so what exactly happened? Did Sync auto-generate another key from the IT installation without telling me, and now all my Sync data is completely lost?

I just had my hard drive replaced recently after it starting giving boot warnings about impending failure. The IT department at my uni replaced the drive, loaded their standard Win7 install, and restored all of my documents and files. Booting Mozilla for the first time on that install, I had all of my bookmarks, setting, passwords, etc. already there (FF even gave me the dialog to restore the last session before the drive replacement.)
But, since their install is awful (tons of bloatware, obnoxious account management and admin privileges, etc.), I decided to go about putting my own copy of 7 on just as I want it. Having learned my lesson with my Sync account last time I did this, I checked to make sure that I still had the recovery key from the original drive/installation (not the IT install.) Now, when I try to use my recovery key, Sync says it's the wrong one, and that "your Recovery Key has been changed with another device." I haven't touched the Key since I first generated it, so what exactly happened? Did Sync auto-generate another key from the IT installation without telling me, and now all my Sync data is completely lost?

More Information

Do you still have the signons.sqlite and key3.db files from the IT setup?

You can find the sync account password and the sync (recovery) key in the password manager on computers where a sync account with a specific e-mail address has been set up.

Look for:

chrome://weave (Mozilla Services Password)

chrome://weave (Mozilla Services Encryption Passphrase)

Do you still have the signons.sqlite and key3.db files from the IT setup?
You can find the sync account password and the sync (recovery) key in the password manager on computers where a sync account with a specific e-mail address has been set up.
Look for:
* chrome://weave (Mozilla Services Password)
* chrome://weave (Mozilla Services Encryption Passphrase)

Question owner

EDIT: I'd also forgotten my Sync password, and had it reset--would that have changed my key?

EDIT EDIT: I do happen to have found the old password, and the encryption phrase that went with it (I'd screenshotted the Saved Passwords window from the original install.) What do I do now?

Where would I find those files?
EDIT: I'd also forgotten my Sync password, and had it reset--would that have changed my key?
EDIT EDIT: I do happen to have found the old password, and the encryption phrase that went with it (I'd screenshotted the Saved Passwords window from the original install.) What do I do now?